qla2xxx crash in qla2xxx_pci_slot_reset() handling recoverable PCI error

Issue

Hardware problem with a Fibre Channel card controlled by qla2xxx driver triggers a system panic in qla2xxx_pci_slot_reset()

The console messages leading up to the panic:

[695071.936118] qla2xxx [0008:81:00.0]-015b:22: Disabling adapter.         <---|--2 adapters are being disabled
[695072.120124] qla2xxx [0008:81:00.1]-015b:23: Disabling adapter.          <---|
[695077.007624] {1}[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 6
[695077.016964] {1}[Hardware Error]: event severity: recoverable
[695077.023383] {1}[Hardware Error]:  Error 0, type: recoverable
[695077.029802] {1}[Hardware Error]:   section_type: PCIe error
[695077.036124] {1}[Hardware Error]:   port_type: 4, root port
[695077.042349] {1}[Hardware Error]:   version: 3.0
[695077.047507] {1}[Hardware Error]:   command: 0x0547, status: 0x4010
[695077.054507] {1}[Hardware Error]:   device_id: 0008:80:00.0
[695077.060731] {1}[Hardware Error]:   slot: 3
[695077.065403] {1}[Hardware Error]:   secondary_bus: 0x81
[695077.071236] {1}[Hardware Error]:   vendor_id: 0x8086, device_id: 0x2030
[695077.078718] {1}[Hardware Error]:   class_code: 000406
[695077.084448] {1}[Hardware Error]:   bridge: secondary_status: 0x6000, control: 0x0003
[695077.095259] pcieport 0008:80:00.0: aer_status: 0x00000000, aer_mask: 0x00000000
[695077.103531] pcieport 0008:80:00.0: aer_layer=Transaction Layer, aer_agent=Receiver ID
[695077.112432] pcieport 0008:80:00.0: aer_uncor_severity: 0x000e7030
[695077.119355] pcieport 0008:80:00.0: broadcast error_detected message
[695077.120564] qla2xxx [0008:81:00.1]-ffff:23: PCI device is disabled,state 2
...
[695078.132086] pcieport 0008:80:00.0: downstream link has been reset
[695078.132091] pcieport 0008:80:00.0: broadcast slot_reset message
[695078.206048] qla2xxx 0008:81:00.0: Refused to change power state, currently i
n D3
[695078.206403] qla2xxx [0008:81:00.0]-00c7:22: MSI-X: Failed to enable support,
 giving   up -- 16/-22.
[695078.206405] qla2xxx [0008:81:00.0]-0037:22: Falling back-to MSI mode --22.
[695078.206406] qla2xxx [0008:81:00.0]-0039:22: Falling back-to INTa mode -- -22.
[695078.206755] qla2xxx 0008:81:00.0: cache line size of 64 is not supported
[695078.206765] qla2xxx [0008:81:00.0]-2009:22: Unable to get host loop ID.
[695078.279127] qla2xxx 0008:81:00.1: Refused to change power state, currently in D3
[695078.279398] BUG: unable to handle kernel NULL pointer dereference at           (null)

The kernel panic stack trace:

crash> bt
PID: 323078  TASK: ffff89d9dcac2080  CPU: 0   COMMAND: "kworker/0:5"
 #0 [ffff89da09cef970] machine_kexec at ffffffff97263b34
 #1 [ffff89da09cef9d0] __crash_kexec at ffffffff9731e242
 #2 [ffff89da09cefaa0] crash_kexec at ffffffff9731e330
 #3 [ffff89da09cefab8] oops_end at ffffffff9796e778
 #4 [ffff89da09cefae0] no_context at ffffffff9795cdfe
 #5 [ffff89da09cefb30] __bad_area_nosemaphore at ffffffff9795ce95
 #6 [ffff89da09cefb80] bad_area_nosemaphore at ffffffff9795d006
 #7 [ffff89da09cefb90] __do_page_fault at ffffffff979716d0
 #8 [ffff89da09cefc00] do_page_fault at ffffffff97971925
 #9 [ffff89da09cefc30] page_fault at ffffffff9796d768
    [exception RIP: qla2xxx_pci_slot_reset+0xd3]
    RIP: ffffffffc0d4c613  RSP: ffff89da09cefce0  RFLAGS: 00010246
    RAX: 0000000000000000  RBX: ffff8b5a13129000  RCX: 0000000000000000
    RDX: 00000000000000fe  RSI: 0000000000000286  RDI: ffff9466f946b000
    RBP: ffff89da09cefd00   R8: 0000000000000002   R9: 000000000000fbff
    R10: 0000000000000001  R11: fffffcd5513f9c80  R12: ffff9466f9469740
    R13: ffff9466f946b000  R14: ffff89da18129800  R15: ffff89da18129800
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
#10 [ffff89da09cefd08] report_slot_reset at ffffffff975d8f76
#11 [ffff89da09cefd30] pci_walk_bus at ffffffff975bb7cb
#12 [ffff89da09cefd68] broadcast_error_message at ffffffff975d86b0
#13 [ffff89da09cefda0] do_recovery at ffffffff975d8899
#14 [ffff89da09cefde0] aer_recover_work_func at ffffffff975d8a1c
#15 [ffff89da09cefe20] process_one_work at ffffffff972baf9f
#16 [ffff89da09cefe68] worker_thread at ffffffff972bc036
#17 [ffff89da09cefec8] kthread at ffffffff972c2e81
#18 [ffff89da09ceff50] ret_from_fork_nospec_begin at ffffffff97976c1d